25/04/62 1 Common Sequences and Clinical Application in MSK‐MRI Pramot Tanutit, MD. Faculty of Medicine, Prince of Songkla University Hat Yai, Songkhla, Thailand April,25 th 2019 Content • Common MR‐sequences in MSK • Imaging planes • Imaging protocols in specific disease and organs Common MR‐sequences in MSK • T1W • Anatomy • Fat, subacute blood • Bone marrow • Tumor staging • Gd • Proteinaceous fluid Common MR‐sequences in MSK • T2W • Anatomy • Fluid • Mass • Cartilage • Muscle T2W‐Fat saturation T2WI and T2W‐FS • Non sensitive • T2W‐non FS: miss some pathology • T2W‐FS: increase sensitivity • Very specific • Assess: tendon, ligament, meniscus • Pitfall: decreased fluid SI if there is hemorrhage (esp. 3T) • Inhomogeneous fat suppression STIR 1 2 3 4 5 6
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Common Sequences Content and Clinical Application in MSK‐MRI
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25/04/62
1
Common Sequences
and
Clinical Application in MSK‐MRI
Pramot Tanutit, MD.
Faculty of Medicine, Prince of Songkla University
Hat Yai, Songkhla, Thailand
April,25th 2019
Content
• Common MR‐sequences in MSK
• Imaging planes
• Imaging protocols in specific disease and organs
Common MR‐sequences in MSK
• T1W
• Anatomy
• Fat, subacute blood
• Bone marrow
• Tumor staging
• Gd
• Proteinaceous fluid
Common MR‐sequences in MSK
• T2W
• Anatomy
• Fluid
• Mass
• Cartilage
• Muscle
T2W‐Fat saturation
T2WI and T2W‐FS
• Non sensitive
• T2W‐non FS: miss some pathology
• T2W‐FS: increase sensitivity
• Very specific
• Assess: tendon, ligament, meniscus
• Pitfall: decreased fluid SI if there is hemorrhage (esp. 3T)
• Inhomogeneous fat suppression
STIR
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3 4
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Common MR‐sequences in MSK
• Proton Density (PD) or intermediate weighted
• Anatomy
• Cartilage
• Labrum
• Ligament
• Tendon/muscle
• Fluid
PD‐Fat Saturation
PDW and PDW‐FS
• PDW‐FS: the most important sequence in MSK imaging
• Very sensitive to define pathology
• Except; sclerosis, fibrosis or fat accumulation‐pathology.
• Inhomogeneous fat suppression esp. in metallic implants due to frequency‐selective fat saturation
STIR
Common MR‐sequences in MSK
• Gradient echo (GRE)
• Blood
• Cartilage/Disc
• Calcification
• Susceptibility artifactsT2W
GRE
Gradient‐echo (GRE)
• Susceptible to artifact
• Easily imitate or miss pathology
• Evaluate cartilage thickness
• Calcification and hemorrhage
T2WT1W
GRE
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Common MR‐sequences in MSK
• Fluid sensitive sequences: T2W‐FS, PDW‐FS, IR.
STIR sequence
• Homogeneous fat suppression
• Fluid sensitive
• Lower resolution than PDW‐FS or T2W‐FS
Common MR‐sequences in MSK
• T1W vs PD
• T1‐SE showed bone marrow best but may isointense with marrow fat on PDW (obscured pathology)
• T1 showed anatomy well but menisci and labrum may be artificially bright due to magic angle effect.
• PD is better than T1 for menisci and tendon
Common MR‐sequences in MSK
Gadolinium administration
• Extension of disease
• Activity of disease
• Tumor vascularity
• Post operation: joints, spine
• Helping detection: small joints or small organs
• Alterative in large joints or large organs
Intravenous contrast administration:Necessary ?
• Detect inflammatory change esp. at the enthesis
• Estimate the extent of synovitis and soft tissue tumor extension
• Differentiate solid from cystic lesion
• Identify necrosis
• Identify scar formation
No Gd‐injection
• Patient deny• History of adverse effect
• Pregnancy • Poor renal function; low GFR (< 30)
•Will discuss in some case
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Pulse sequences
Artifact depends on Hardware Composition: susceptibility of metals
• Bad sequences: GRE, Fat‐saturation, (spin echo)
• Good sequences: FSE, IR
• Bad metals• Stainless steel: large artifacts, plates and screws• Cobalt chrome: moderate artifacts, older hip, bipolar hips and knees
• Good metals• Titanium:minimal artifacts. Newer hips, IM nail
• Oxidized Zirconium: oxinium, moderate artifact
Imaging planes
• Anatomical position:
• Scout images: landmarks
• Coronal‐Axial‐Transverse: foot, sacrum/ SI joints, hip